CONSTITUTION AND DEVELOPMENT OF TERMITES. 313 
quickly gnaw through the cork and escape. This happens even 
if the wings have fallen off. ; 
It will be recollected that the two sexes swarm at different 
times. This is demonstrated by— 
1. The fact that all members of a swarm are found to be 
of the same sex. 
2. The presence in many nests, late in or at the end of the 
swarm-period, of black winged forms, which are all males or 
all females only (by a rare exception a single male may be 
found to every twenty or thirty females), whereas nests in which 
the imagos are still white contain a male to every two or three 
females. 
The convulsive movements spoken of under Calotermes 
are exhibited alike by Termes, and are common to all mem- 
bers of the colony except the newly born, and have the same 
significance. Moreover the soldier is able simultaneously to 
produce a special crepitus (creaking), which arises whenever 
the head is held horizontally during the act of quivering by 
friction between the hind margin of the occiput and the ante- 
rior margin of the pronotum. But whenever the head is held 
in the normal position during the act—that is, somewhat de- 
flexed—no perceptible sound is produced, owing to the absence 
of friction. 
The soldiers, therefore, possess two distinct modes of commu- 
nication ; and itis noticeable that those of Calotermes always 
hold the head obliquely deflexed when quivering and produce 
no sound, 
I may add that this characteristic crepitus may be heard at 
very short intervals by applying the ear to a trunk containing 
a nest of Termites. This proves that the quivering motions 
are a constant feature in normal and undisturbed nests, in 
which they are therefore not employed to give indications of 
alarm or distress; and I conclude that, besides these signifi- 
cations, the convulsive movements must also have the value of 
ordinary speech ; that they constitute, in short, a means of in- 
tercommunication. The same conclusion holds good for Calo- 
